Expose Sentry Testkit to localhost

[cvalarida]

User Story

As a VSP / VSA engineer, I need to see when my code is sending events to Sentry from localhost so I can ensure it's functioning properly even before writing unit tests.

This is especially useful when performing experiments where it may not make sense to write up a whole unit test yet.

Goal

When running the localhost build, we have access to all the events that would have been sent to Sentry without actually sending them there.

Currently, we don't even initialize the Sentry client for localhost.

Acceptance Criteria

For localhost builds:

• [ ] The Sentry client is set up to use Sentry Testkit
• [ ] Sentry Testkit is accessible via the developer tools console

For other builds:

• [ ] The Sentry client is set up to send events to our Sentry server (like it is now)
• [ ] The Testkit isn't part of the JavaScript bundle sent to the client

Definition of Done

• [ ] Attached to a Milestone (when will this be completed?)
• [ ] Attached to an Epic (what body of work is this a part of?)
• [ ] Labeled with Team (product support, analytics-insights, operations, triage, tools-improvements)
• [ ] Labeled with Practice Area (backend, frontend, devops, design, research, product, ia, qa, analytics, call center, research, accessibility, content)
• [ ] Labeled with Type (bug, request, discovery, documentation, etc.)

[alexpappasoddball]

@cvalarida figure out if this is something that will be beneficial.

[cvalarida]

I asked the larger FE team and there were folks who sounded interested, but I don't know that it's worth our time until somebody runs into a situation where this would be legitimately helpful.